147 GTA Problem: Motor Control System Failure

[Brad M]

However, I noticed the idle doesn't appear to be as smooth as I remember it to be. Almost feels like a very slight miss fire occasionally when idle but when the car is going and revving higher, it seems fine. Anyone have any ideas what could have transpired or is that normal? Would a tooth out on one of the cams cause that?

I'm interested in the solution, my 05 GTA has a similar rough idle, it was suggested to me it was spark plugs which I have yet to change over (on account of having to take the manifold off). If I get around to changing the spark plugs, I'll let you know if it fixes the problem.

[155 lover]

Nice advice and discussion from everyone on the belts - appreciate all the advice.

Anyway, further to my original problem, I got the car back, but it just doesn't "sound" the same (slightly rough-ish sound coming from the engine, not the exhaust) and the mechanic did not do anything except replace brake fluid, change the clutch slave and clutch master cylinders. Added to this, the comments from the mechanic are not encouraging me that he thoroughly checked the "motor control system failure" message I got. He said the warning code he read on the computer was related to coolant temperature.

Given that I got the MCSF warning when on the freeway (at about 130km/h), and knowing that the plastic water pump impellors can go funny at freeway speeds (I read this somewhere on the forum - correct me if I'm wrong), I'm now wondering if the original owner did the water pump when they did the belt at 27,000kms, and if that could be the cause of the MCSF warning. The dealer has the receipt number for the timing belt and they claim that they always do the pump at the same time as the belt, but he told me the pump wasn't listed as a part, so I have to question it.

Either way I've decided not to chance it, I'm going to take it to a different mechanic and get the water pump and belt done and be done with it.

Thanks again for the experiences and advice provided - very helpful indeed.

To colcol - I initially questioned the expense for the belts and water pump because I know the layout of the engine bay in the GTA (and in other alfas) just isn't conducive to working on cheaply. I.e. to change a parker light bulb, I need to remove the bumper is just one example. I know you can expect increased service costs with an alfa, but I wonder if they had spent a few more $$ on design and forward thinking about servicing needs, if they could not have reduced the labour hours required to service the car. I've got no problem with more expensive parts and designs to improve performance - that's what makes an Alfa special, but I can't help but wonder to what extent they could have spent some money laying out the engine in such a way that improves access and reduces servicing costs associated with labour.

[wankski]

alfa did a very good job...

its a 400lb monster v6 in a fwd layout in a engine bay designed for 4cyl...

GTAs came later, shoehorned into the 4 banger cooking model.. 4 banger in a transverse layout is bad enuff... make it a v6 the size of a small v8 and ain't nuthin' u can really do about it...

[colcol]

Could not agree more, a bit more thought should be put into these things such as accesable bolts or panels that unbolt to get to things, they need to say to the designers, ok you designed it, now you show us how to fix it in an hour, and talking of cam belt changes in WRX's and STI's, at work, one of the junior engineers decided that he better change the cam belts in his WRX, because it was 10 years old and it had done 130,000, but because they are Turbocharged they run low compression and have generous valve to piston clearance, it is not the must do ticket like it is in Alfa's, Colin.

[155 lover]

Yeah I know they did well to fit it in there, and it's awesome having that 3.2 V6 in the 147 body, however there's nothing that a good bit of engineering can't improve on. As colcol said, having made the car, I just think Alfa could have spent more time and effort into making sure things are as easily accessible as possible and at the moment, I don't think they are when you have to work on the car.

Oh and I'm getting the timing belt and water pump done next Thursday if all goes to plan. A small fortune but at least I'll be able to drive it without worrying.

[155 lover]

UPDATE:
After all the discussion and good advice on this forum, I wasn't happy with my first mechanic's diagnosis with regards to the motor control system failure and the cooling system and frankly it seemed a lot like blatant disregard for my suggestions. I took it to another specialist alfa mechanic with my concerns - basically all the discussion on here and previous posts, combined with the symptoms the car was displaying suggested a possible cracked plastic water pump impellor. I did a lot of reading on it and I was pretty convinced this could be the problem given that the previous dealer couldn't verify if they did the water pump with the timing belt at 27,000kms.

Anyway, I decided to do the timing belt and water pump because it was a little over 3 years with the new mechanic and sure enough, I just received a phone call letting me know that the plastic impellor is completely cracked, although it's not yet spinning. Overall I'm pretty happy that they found the problem and it's pretty straight forward and common, so I'll be getting the new water pump with the metal impellor.

A big thank you to all those that commented and provided advice - a good outcome in the end, everything else is in good condition.

Lastly, what oil should I be running in the GTA? Just for my own knowledge really - the mechanic recommended a fully synthetic oil I think - castrol edge sport or something.

[wankski]

Lastly, what oil should I be running in the GTA? Just for my own knowledge really - the mechanic recommended a fully synthetic oil I think - castrol edge sport or something.

god job getting it sorted!!

GTA manual spec: 10w-60 API SL and ACEA A3.

Yes castrol edge 10w-60 is a good substitute for the spec'd selenia.

[gbernard]

I had a similar issue  re the rough idle and almost sounding like an occassional misfire after belts were done.

And new coil packs and new plugs . .

did you resolve this and how BTEOH and Brad ?

[wankski]

the problem is marking the pulleys instead of the correct procedure to strip all pulleys from their taper lock - using proper cam locks and starting the timing again as reference from TDC cyl1.

common.

[wankski]

http://www.alfaowner.com/Forum/alfa-164-and-166/212058-166-3-0-terribly-rough-idle-knocking-noise-after-cambelt-2.html

timing must be done 100% correctly, u can rely on NO factory markings... and the pulley MUST come off.

[gbernard]

wankski, it was done properly, the timing was checked with camlocks, with cyl 1 at TDC, and the cam locks slotted in perfectly.

they found the new spark plugs had a white coating, and I suspect (i sourced them from overseas) they weren't the right heat range, also the decarbonised the intake runners and plenum, seem to have improved quite a bit, but the uneven idle (happens only intermittently) is still there, but I will do an ecu reset and see if that helps further.

[wankski]

yeah, it's just in most cases if it happens right after belt change...

correct plugs are NGK R PFR6B.